An isotope of yttrium has 39 protons and 59 neutrons. What is the mass number of that isotope?

Melting and boiling are endothermic processes. this means that these processes absorb energy from their surroundings in order to occur. use this information and the data you collected in the phase change gizmo to describe what happens to the temperature of water when you boil it, then explain why this result occurs.

Consider the elements bromine and chlorine; which elements has a larger ionic radius ?

What determines the average kinetic energy of the particles in a gas? a. the number of collisions b. the number of particles c. the size of the particles d. the temperature